1. Field of the Invention
The present invention relates to impact and wear resistant material, and, more particularly to impact and wear resistant material fabricated with boron nitride nanotubes (BNNTs).
2. Description of Related Art
Micrometeoroids develop very high kinetic energies as they travel through space and pose a significant hazard to spacecraft and astronauts. The velocities of the micrometeorites can reach 20 kilometers per second prior to impact on the lunar surface [Eagle Engineering Incorporated, “Lunar Base Environment Report”, Kennedy Space Center, July, 1989]. Therefore an improved protective system utilizing new materials is needed to effectively shield space vehicles and structures against high kinetic energy penetrators as well as to provide penetration resistant space suits. In addition, new lightweight, conformable body armor for protection against high kinetic energy penetrators such as bullets and shrapnel, whilst providing increased mobility, has been sought for accomplishing successful missions on the modern battlefield.
Some materials have been considered for protection against high-speed penetrating impacts. Both non-metallic and metallic materials are often used for the protection. The non-metallic protective materials include Aramid (Kevlar®), ultra high molecular weight polyethylene (Spectra®), Mylar®, Fiberglass, Nylon, Nomex®, or ceramic composite plates [W. J. Perciballi, U.S. Pat. No. 6,408,733]. Carbon nanotubes and their composites have been suggested as well [K. Mylvaganam and L. C. Zhang, “Ballistic resistance capacity of carbon nanotubes,” Nanotechnology, 47, 475701 (2007)]. The metallic protective materials include titanium and steel. Some of these materials have been proven to be highly protective against the high kinetic energy penetrators [F. J. Stimler, “System Definition Study of Deployable Non-metallic Space Structures”, Goodyear Aerospace Corporation, Report No. GAC 19-1615; NASA Contract NAS8-35498, June 1984].
Materials manufactured from heavy inorganic materials (metals and ceramics) have been used to achieve materials for use in environments where wear-resistant qualities are required.
State-of-the-art polymeric protective materials such as Kevlar® and Spectra® show poor thermal stability. The metallic or ceramic protective materials are very heavy, resulting in increased launch costs for space applications. Due to weight restrictions, these materials cannot be used in new space vehicle/structure concepts such as inflatable habitats and solar sails. Body armor fabricated with these materials provides little comfort and greatly restricts the wearer's mobility; as a result its use is often limited primarily to body torso protection.
Although carbon nanotubes are useful in high temperature environments up to 400° C., they oxidize and burn at temperatures above 400° C. so alternate materials are sought for use in environments experiencing temperatures above 400° C. As shown in FIG. 5, BNNT materials have significant advantages in such high-temperature environments.
In certain applications, heavy, inorganic metals are used to achieve high wear resistance. Such metals increase the weight and reduce the efficiency of the apparatus.
In recent years, anti-penetration materials have been more and more widely used for protective apparel, bullet-proof vests, and micrometeoroid and orbital debris protection layers for space suits as well as space vehicles and structures.
In order to maximize the protection ability of a material against high kinetic energy penetrators, the following two major material properties should be considered: (1) high hardness for rebounding and/or gross mechanical deformation of the penetrator; and (2) high toughness for effective energy absorption during the mechanical deformation (and heat) of the protecting materials.
It is a primary aim of the present invention to provide a lightweight high kinetic energy penetration protection material fabricated with boron nitride nanotubes (BNNTs) and BNNT composites to maximize the energy absorption in the course of mechanical deformation, and heat, of the protecting materials under an impact.
It is an object of the invention to provide a lightweight high kinetic energy penetrator protection material fabricated with high hardness particles, such as boron nitride based nanoparticles (BNP) and BNP composites, to maximize rebounding of the penetrator or for gross mechanical deformation of the penetrator.
It is an object of the invention to provide materials having high wear resistance, and thus prolonged usage time of such materials under harsh abrasive conditions, such as battlefields and space environments, by improving hardness and toughness through the use of boron nitride nanomaterials.
It is an object of the invention to provide a lightweight high kinetic energy penetrator protection material fabricated with carbon nanotubes (CNTs), graphites, graphene oxides and their composites to maximize the energy absorption via mechanical deformation (and heat) of the protective materials.
It is an object of the invention to provide lightweight, high wear resistance materials fabricated with boron nitride nanotubes (BNNTs), boron nitride based nanoparticles (BNPs), boron-carbon-nitride nanotube (BxCyNz nanotubes), carbon nanotubes (CNTs), graphites, and their composites to prolong the usage time at a severe abrasion condition.
It is an object of the invention to provide a lightweight, ultra hard and tough BNNT fiber/woven/non-woven composite mat for flexible armor.
It is an object of the invention to provide a lightweight, high kinetic energy penetrator protection material fabricated with boron nitride nanotubes (BNNTs), boron nitride nanoparticles (BNPs), boron-carbon-nitride nanotubes (BxCyNz nanotubes), carbon nanotubes (CNTs), graphites, graphene oxides, metal coated nanoinclusions, metal particles and their composites to minimize a locally concentrated heating damage via increasing thermal conductivity.
It is a further object of the invention to provide a lightweight, ultra hard and tough BNNT fiber/woven/non-woven composite mat for space suit layers and deployable space craft systems.
Finally, it is an object of the present invention to accomplish the foregoing objectives in a simple and cost effective manner.
The above and further objects, details and advantages of the invention will become apparent from the following detailed description, when read in conjunction with the accompanying drawings.